966 research outputs found
Equations of motion of test particles for solving the spin-dependent Boltzmann-Vlasov equation
A consistent derivation of the equations of motion (EOMs) of test particles
for solving the spin-dependent Boltzmann-Vlasov equation is presented. The
resulting EOMs in phase space are similar to the canonical equations in
Hamiltonian dynamics, and the EOM of spin is the same as that in the Heisenburg
picture of quantum mechanics. Considering further the quantum nature of spin
and choosing the direction of total angular momentum in heavy-ion reactions as
a reference of measuring nucleon spin, the EOMs of spin-up and spin-down
nucleons are given separately. The key elements affecting the spin dynamics in
heavy-ion collisions are identified. The resulting EOMs provide a solid
foundation for using the test-particle approach in studying spin dynamics in
heavy-ion collisions at intermediate energies. Future comparisons of model
simulations with experimental data will help constrain the poorly known
in-medium nucleon spin-orbit coupling relevant for understanding properties of
rare isotopes and their astrophysical impacts.Comment: 5 page
Neuroprotective effects of lomerizine on retinal ganglion cells in the diet-induced obese C57BL/6J mice
AIM: To research the neuroprotective effects of lomerizine(LOM)on retinal ganglion cells(RGCs)in the diet-induced obese C57BL/6J mice. <p>METHODS: Fifty-four mice were randomly divided into two groups which were fed a high-fat diet for 19wk. One group mice were lavaged LOM by the dosage of 80mg/kg daily at the same time. The obese mice were selected and divided into diet-induced obesity(DIO)group, diet-induced obesity and lomerizine(DIO+LOM)group. The mice in the control(CON)group were fed a basal diet. The ultrastructural changes of RGCs were detected by transmission electron microscope. The cellular apoptosis was detected by TUNEL. The laser scanning confocal microscope was used to measure intracellular calcium ion concentration. <p>RESULTS: Compared with the CON group, the RGCs in DIO group showed smaller and condensation of nuclear chromatin and increased electron density of the cytoplasm, whereas the changes in DIO+LOM mice were obviously diminished. TUNEL staining showed that the number of apoptosis cells in the ganglion cell layer(GCL)increased in DIO group and the percentage of apoptotic cells was much higher than that in the CON groups(<i>P</i><0.01). The DIO+LOM group mice showed fewer apoptosis cells and the percentage of apoptotic cells in this group were significantly decreased than the DIO mice(<i>P</i><0.05). The Laser scanning confocal microscope detection showed Ca<sup>2+</sup> staining intensity of RGCs in DIO group increased and its staining intensity ratio was significantly higher than in CON group(<i>P</i><0.01), the Ca<sup>2+</sup> staining intensity and its staining intensity ratio in DIO+LOM group were significantly decreased than the DIO group(<i>P</i><0.01). <p>CONCLUSION: Lomerizine has neuroprotective effects on damage of retinal ganglion cells in diet-induced obesity mice, which may be related to the attenuation of intracellular Ca<sup>2+</sup> overload
New progress of ranging technology at Wuhan Satellite Laser Ranging Station
A satellite laser ranging system with an accuracy of the level of centimeter has been successfully developed at the Institute of Seismology, State Seismological Bureau with the cooperation of the Institute of Geodesy and Geophysics, Chinese Academy of Science. With significant improvements on the base of the second generation SLR system developed in 1985, ranging accuracy of the new system has been upgraded from 15 cm to 3-4 cm. Measuring range has also been expanded, so that the ETALON satellite with an orbit height of 20,000 km launched by the former U.S.S.R. can now be tracked. Compared with the 2nd generation SLR system, the newly developed system has the following improvements. A Q modulated laser is replaced by a mode-locked YAG laser. The new device has a pulse width of 150 ps and a repetition rate of 1-4 pps. A quick response photomultiplier has been adopted as the receiver for echo; for example, the adoption of the MCP tube has obviously reduced the jitter error of the transit time and has improved the ranging accuracy. The whole system is controlled by an IBM PC/XT Computer to guide automatic tracking and measurement. It can carry out these functions for satellite orbit calculation, real-time tracking and adjusting, data acquisition and the preprocessed of observing data, etc. The automatization level and reliability of the observation have obviously improved
Neuroprotection of Catalpol for Experimental Acute Focal Ischemic Stroke: Preclinical Evidence and Possible Mechanisms of Antioxidation, Anti-Inflammation, and Antiapoptosis
Neuroprotection is defined as using a therapy that affects the brain tissue in the still-viable ischemic penumbra to salvage or delay the infarction. Catalpol, the main active principle of the root of Radix Rehmanniae, was reported to have pleiotropic neuroprotective effects in neurodegenerative diseases including ischemic stroke. Here, we evaluated the neuroprotective effects of catalpol in experimental acute ischemic stroke. Studies on catalpol in animal models of acute ischemic stroke were identified from 6 databases. Twenty-five studies involving 805 animals were included. Twelve comparisons showed significant effects of catalpol on decreasing infarct size according to 2,3,5-triphenyltetrazolium chloride staining compared with the control (P<0.05). One study reported significant effect of catalpol on reducing infarct size according to magnetic resonance imaging scan compared with the control (P<0.05). Meta-analysis of these studies indicated that catalpol significantly improved the neurological function score according to Zea Longa score, Bederson score, balance beam-walking test, adhesive removal test, bar-grasping score, and corner test compared with the control (P<0.05). In conclusion, catalpol exerted neuroprotective effects for experimental acute focal ischemic stroke, largely through reducing oxidative reactions, inhibiting apoptosis, and repressing inflammatory reactions and autophagy. However, these apparently positive findings should be interpreted with caution because of the methodological flaws
The Differential Role of Human Cationic Trypsinogen (PRSS1) p.R122H Mutation in Hereditary and Nonhereditary Chronic Pancreatitis: A Systematic Review and Meta-Analysis.
Background:Environmental factors and genetic mutations have been increasingly recognized as risk factors for chronic pancreatitis (CP). The PRSS1 p.R122H mutation was the first discovered to affect hereditary CP, with 80% penetrance. We performed here a systematic review and meta-analysis to evaluate the associations of PRSS1 p.R122H mutation with CP of diverse etiology. Methods:The PubMed, EMBASE, and MEDLINE database were reviewed. The pooled odds ratio (OR) with 95% confidence intervals was used to evaluate the association of p.R122H mutation with CP. Initial analysis was conducted with all etiologies of CP, followed by a subgroup analysis for hereditary and nonhereditary CP, including alcoholic or idiopathic CP. Results:A total of eight case-control studies (1733 cases and 2415 controls) were identified and included. Overall, PRSS1 p.R122H mutation was significantly associated with an increased risk of CP (OR = 4.78[1.13-20.20]). Further analysis showed p.R122H mutation strongly associated with the increased risk of hereditary CP (OR = 65.52[9.09-472.48]) but not with nonhereditary CP, both alcoholic and idiopathic CP. Conclusions:Our study showing the differential role of p.R122H mutation in various etiologies of CP indicates that this complex disorder is likely influenced by multiple genetic factors as well as environmental factors
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